System and method for digital multimedia broadcasting

ABSTRACT

Provided is a digital multimedia broadcasting (DMB) system that can provide a multimedia data broadcasting service having an excellent reception quality, a method thereof, and a computer-readable recording medium for recording a program that implements the method. The DMB system includes an encoding unit for encoding an inputted audio/video signal; a synchronizing unit for synchronizing media stream, additional data, interactive service objectifying data that are outputted from the encoding unit; a multiplexing unit for multiplexing the media stream outputted from the synchronizing unit; an error correction encoding unit for performing additional error correction encoding on the media stream outputted from the multiplexing unit; an interleaving unit for removing temporal correlation between adjacent byte units within a data stream outputted from the error correction encoding unit; and a transmitting unit for transmitting a DMB media stream outputted from the interleaving unit to the conventional DAB system and other digital broadcasting systems.

TECHNICAL FIELD

The present invention relates to a digital multimedia broadcasting (DMB)system for transmitting mobile television (TV) contents, e.g., video andvideo-related multimedia data, based on a digital audio broadcasting(DAB) system and other diverse digital broadcasting systems, a methodthereof, and a computer-readable recording medium for recording aprogram that implements the method.

BACKGROUND ART

A conventional digital audio broadcasting (DAB) and other diversedigital broadcasting systems define only basic mechanism such as streammode and packet mode based on the presence of a synchronization signalwithin a stream to transmit a data stream. They simply define only atransmission format of data stream but they do not include any specificmethod for effective and stable transmission of video and multimediadata. Also, most of them apply only a single error correction code toovercome system performance degradation caused by multi-path fading andthe Doppler effect in a mobile radio channel environment. This isbecause they are designed in consideration of a performance target valueof audio or a low quality data service only. For example, in case ofDAB, a target Bit Error Rate (BER) is 1×10⁻⁴ (BER=1×10⁻⁴). However, inorder to satisfy a stable mobile reception quality of video andmultimedia data, the target BER should be at least 10 ⁻⁸ and it is veryhard to obtain the BER value in the conventional DAB system and otherdigital broadcasting systems designed only for audio service.

Therefore, required necessarily is a new DMB transmission scheme fortransmitting high quality multimedia data, which is compatible with thetransmission standard of the DAB and other diverse digital broadcastingsystems.

Meanwhile, the DAB will be described more in detail by taking an exampleof the Eureka 147 DAB system, which is a DAB system of the Europe.

FIG. 1 is an exemplary diagram showing a conventional Eureka 147 DABsystem.

Since the latter half of 1980's, European countries have activelyundertaken research on DAB transmission scheme that can provide ahigh-quality audio service in mobile reception by organizing the Eureka147 joint project. Since 1992, a Coded-Orthogonal Frequency DivisionMultiplexing (COFDM), which is a multi-carrier modulation scheme strongat multi-path fading, and a Moving Picture Experts Group (MPEG)-1/-2Layer II, which is a signal compression method for transmitting ahigh-quality audio program, have been embodied and tested for theirperformance. By the early 1995, a DAB transmission scheme of a Europeansingle standard was developed.

In the DAB system having a transmission scheme as shown in FIG. 1, audiodata stream encoded by using the MPEG encoder or ordinary data streampasses through an energy dispersal scrambler to disperse the energy ofthe radio frequency (RF) transmission signal and then it is encoded byusing convolutional encoder at a different encoding rate based onUnequal Error Protection (UEP) or Equal Error Protection (EEP) profile.Then, sub-channel data which are time-interleaved with respect to 16logical frame sections are multiplexed in the Main Service Multiplexer(MSM) to thereby form Common Interleaved Frame (CIF). Herein, since eachlogical frame includes information of a 24 ms section in a time domain,the total depth of interleaving is 384 ms. In order to form a 24ms-based DAB transmission frame, a synchronous channel, a FastInformation Channel (FIC), and a Main Service Channel (MSC) foreffective data transmission are created and Quadrature Phase ShiftKeying (QPSK) symbol mapping is performed. Then, frequency interleavingis applied in order to minimize the influence on the frequency selectivefading.

Subsequently, a phase reference signal is generated and placed in thesecond symbol of the transmission frame and differential modulation isperformed on the Orthogonal Frequency Division Multiplexing (OFDM)symbol that forms the FIC and MSC based on the phase reference signal.Each OFDM symbol that forms a transmission frame goes throughzero-padding for 2N Inverse Fast Fourier Transform (IFFT) and then it isconverted into a time domain signal through the IFFT.

In the meantime, data corresponding to a fourth of the rear of aneffective symbol section are inserted to the front of the effectivesymbol and transmitted in order to remove Inter-Symbol Interference(ISI). This is called guard interval.

At present, most of the European countries, Canada, Singapore, and Chinaare in service or in preparation of regular DAB broadcasting and Korea,too, selected the Eureka 147 DAB transmission scheme as transmissionstandard for digital audio broadcasting in the late 2002.

However, in case of the DAB, since a DAB transmission scheme forproviding an effective and stable high-quality multimedia data servicein a mobile channel is not developed both in Korea and other countries,it is required to develop a new DMB transmission scheme.

DISCLOSURE OF INVENTION

It is, therefore, an object of the present invention to provide adigital multimedia broadcasting (DMB) system that can provide multimediadata broadcasting service with a high reception quality in a mobileenvironment by applying highly efficient compression and objectificationof multimedia data, synchronization and multiplexing between mediastreams, additional error correction method and interleaving in order tosecure stable reception quality of multimedia data in a mobile channelenvironment and embody efficient and interactive multimedia databroadcasting by using a conventional digital audio broadcasting (DAB)system and other diverse digital broadcasting systems; a method thereof;and a computer-readable recording medium for recording a program thatimplements the method.

It is another object of the present invention to provide a DMB systemthat can embody DMB without changing the conventional DAB and otherdigital broadcasting systems by operating in a perfect compatibilitywith the conventional digital broadcasting system, because it isdesigned in consideration of the conventional DAB system and otherdiverse digital broadcasting systems; a method thereof; and acomputer-readable recording medium for recording a program thatimplements the method.

In accordance with one aspect of the present invention, there isprovided a DMB system, which includes: an encoding unit for encoding aninputted audio/video signal; a synchronizing unit for synchronizingmedia stream, additional data, interactive service objectifying datathat are outputted from the encoding unit; a multiplexing unit formultiplexing the media stream outputted from the synchronizing unit; anerror correction encoding unit for performing additional errorcorrection encoding on the media stream outputted from the multiplexingunit; an interleaving unit for removing temporal correlation betweenadjacent byte units within a data stream outputted from the errorcorrection encoding unit; and a transmitting unit for transmitting a DMBmedia stream outputted from the interleaving unit.

In accordance with one aspect of the present invention, there isprovided a digital DMB method, which includes the steps of: a) encodingvideo/audio data at a high efficiency for data compression; b)synchronizing a media stream encoded in the step a), a media stream foran additional data service, and a objectified media stream for aninteractive service; c) multiplexing a media stream synchronized in thestep b); d) encoding and interleaving for correcting an error to beoccurred in a media stream multiplexed in the step c); and e)transmitting a stream interleaved in the step d).

In accordance with one aspect of the present invention, there isprovided a computer-readable recording medium for recording a programthat implement a digital DMB method, which includes the steps of: a)encoding video/audio data at a high efficiency for data compression; b)synchronizing a media stream encoded in the step a), a media stream foran additional data service, and an objectified media stream for aninteractive service; c) multiplexing a media stream synchronized in thestep b); d) encoding and interleaving for correcting an error to beoccurred in a media stream multiplexed in the step c); and e)transmitting a stream interleaved in the step d).

Meanwhile, the DMB system of the present invention includes abroadcasting field where multimedia data are transmitted by usingconventional DAB and digital broadcasting systems, a field of sourceencoding technology where multimedia data are compressed, a field ofmultiplexing technology where multimedia data streams are mixed, and afield of error correction encoding technology where robustness to errorgenerated in a mobile channel is given.

BRIEF DESCRIPTION OF DRAWINGS

The above and other objects and features of the present invention willbecome apparent from the following description of the preferredembodiments given in conjunction with the accompanying drawings, inwhich:

FIG. 1 is an exemplary diagram showing a conventional Eureka 147 digitalaudio broadcasting (DAB) system;

FIGS. 2A and 2B are diagrams describing a transmission method of adigital multimedia broadcasting (DMB) system in accordance with anembodiment of the present invention;

FIGS. 3A and 3B are block diagrams illustrating a DMB system inaccordance with an embodiment of the present invention;

FIG. 4 is a block diagram showing a media processor of the DMB system inaccordance with an embodiment of the present invention;

FIGS. 5A and 5B are diagrams describing a Reed-Solomon (RS) encoder ofthe DMB system in accordance with an embodiment of the presentinvention;

FIG. 6 is a schematic diagram describing an interleaver of the DMBsystem in accordance with an embodiment of the present invention;

FIG. 7 is a block diagram describing an apparatus for cooperating theDMB system and the conventional DAB system in accordance with anembodiment of the present invention;

FIG. 8 is a block diagram describing an apparatus for cooperating theDMB system and the conventional DAB system in accordance with anotherembodiment of the present invention;

FIG. 9 is a flowchart describing an Ensemble Transport Interface (ETI)frame forming method in accordance with an embodiment of the presentinvention; and

FIG. 10 is a block diagram illustrating an apparatus for cooperating theDMB system and the conventional DAB system in accordance with yetanother embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Other objects and aspects of the invention will become apparent from thefollowing description of the embodiments with reference to theaccompanying drawings, which is set forth hereinafter.

FIGS. 2A and 2B are diagrams describing a transmission method of adigital multimedia broadcasting (DMB) system in accordance with anembodiment of the present invention.

As shown in FIG. 2A, the DMB system of the present invention includes aprocess of high-efficiency video encoding at step 201 for compressingvideo data, a process of high-efficiency audio encoding for compressingaudio data at step 202, a process of insertion of additional data atstep 203, a process of objectification for interactive service at step204, a process of synchronization at step 210 for synchronizing mediastreams outputted from the processes of video encoding at the step 201,audio encoding at the step 202, additional data insertion at the step203, and objectification for interactive service at the step 204, aprocess of multiplexing for mixing the synchronized media streams atstep 220, and a process of encoding and interleaving for correcting anerror to be occurred in the media stream multiplexed in the process ofmultiplexing and interleaving at step 230.

The DMB system transmits DMB data as follows.

First, at the steps 201 and 202, high-efficiency source encoding forcompressing multimedia data is performed and, at the step 204,objectification for interactive service is performed. Then, at the step210, video/audio/additional data streams are synchronized and, at step220, the media streams are multiplexed.

Subsequently, at step 230, error correction encoding and interleavingare performed on the multiplexed stream in order to secure excellentreception quality in a high-speed mobile channel environment. The streamobtained by using the error correction encoding and the interleaving istransmitted to the DAB system and other digital broadcasting systems.Herein, the digital broadcasting systems include a digital television(TV) broadcasting system, a digital satellite broadcasting system, and adigital cable broadcasting system.

Meanwhile, if the DAB system and the digital broadcasting system showexcellent system performance in a high-speed mobile channel environment,a DMB transmission scheme as shown in FIG. 2B which does not include theerror correction encoding and interleaving of the step 230 can beapplied.

FIGS. 3A and 3B are block diagrams illustrating a DMB system inaccordance with an embodiment of the present invention. The drawingsshow system technologies applied to the DMB of FIGS. 2A and 2B.

As shown in FIG. 3A, the DMB system of the present invention can bedivided into a DMB transmitter 310 and a DMB receiver 320.

First, the DMB transmitter 310 uses an MPEG-4 audio encoder 311 and anMPEG-4 video encoder 312 for high-efficiency source encoding, and ituses an MPEG-4 systems encoder 313 for objectification andsynchronization of media stream. It uses an MPEG-2 transport stream (TS)multiplexer 314 for multiplexing media stream, and it uses aReed-Solomon (RS) encoder 315 for additional error correction encoding.The DMB transmitter 310 uses a convolutional byte interleaver 316 toremove temporal correlation between neighboring byte units in datastream. The finally outputted DMB media stream is inputted through astream mode of a DAB transmission system 317 or data channels of theother digital broadcasting systems.

The DMB receiver 320 receives multimedia data, which are passed througha receiving channel of the DAB receiving system 321 or those of theother digital broadcasting systems, pass through the convolutional bytedeinterleaver 322, the RS decoder 323, the MPEG-2 TS demultiplexer 324,the MPEG-4 systems decoder 325, the MPEG-4 video decoder 326, and theMPEG-4 audio decoder 327.

If the conventional digital broadcasting systems 317 and 321 showexcellent system performance in the high-speed mobile channelenvironment, a DMB transmission scheme can be embodied without themultiplexing process and the error correction encoding and interleavingprocess, which is shown in FIG. 3B.

FIG. 4 is a block diagram showing a media processor of the DMB system inaccordance with an embodiment of the present invention. It shows astructure of a DMB media processor that performs functions fromcompression to multiplexing of multimedia data. Herein, the mediaprocessor includes an MPEG-4 video/audio encoder, an MPEG-4 systemsencoder, and an MPEG-2 TS multiplexer.

As shown in FIG. 4, the media processor of the DMB system of the presentinvention includes a preprocessor 410, an MPEG-4 encoder 421 and 422, anobject descriptor (OD)/binary format for scene (BIFS) generator 431, anInitial Object Descriptor (IOD) generator 432, a sync layer (SL)packetizer 433, a Program Elementary Stream (PES) packetizer 441, a14496 section packetizer 442, a PSI generator 443, a TS packetizer 444.

The preprocessor 410 converts an audio/video signal into a data streamof a desired format. The MPEG-4 encoder 421 and 422 compresses the datastream outputted from the preprocessor 410 into a high compressed mediastream. The OD/BIFS generator 431 generates object descriptor (OD) andbinary format for scene (BIFS). The IOD generator 432 generates theinitial object descriptor (IOD). The sync layer packetizer 433synchronizes media streams outputted from the MPEG-4 encoder 421 and 422and the OD/BIFS generator 431. The PES packetizer 441 packetizes apacket outputted from the sync layer packetizer 433 into a PES packet.The 14496 section packetizer 442 packetizes a packet outputted from thesync layer packetizer 433 into a 14496 section. The PSI generator 443generates Program Service Information (PSI) based on the data outputtedfrom the IOD generator 432. The TS packetizer 444 packetizes a packetoutputted from the PES packetizer 441, 14496 section packetizer 442, PSIgenerator 443 into transport stream.

That is, the media processor of the DMB system of the present inventionincludes an MPEG-4 systems encoder 430 and an M4overM2 module 440. TheMPEG-4 systems encoder 430 includes the MPEG-4 audio/video encoder 421and 422 for performing media compression efficiently after convertingthe audio/video multimedia source data into a data steam of a desiredformat in the preprocessor 410, the OD/BIFS generator 431 forinteractive service, the IOD generator 432, the sync layer packetizer433 for synchronizing the media streams, and the M4overM2 module 440 forgenerating a program elementary stream (PES) packet based on a synclayer packet and multiplexing the PES packet with a section packet andProgram Service Information (PSI) into an MPEG-2 transport stream.Herein, the TS packetizer 444 can multiplex one or moreaudio/video/additional data based on a program.

As for the video encoder, an ‘MPEG-4 Part 2’ codec and an ‘MPEG-4 Part10 Advanced Video Coding (AVC)’ codec can be used. For the audioencoder, diverse codecs such as an ‘Advanced Audio Coding (AAC)’ codec,an ‘AAC+’ codec, and a ‘Bit Sliced Arithmetic Coding (BSAC)’ codec canbe used. The codec is selected in consideration of compressionperformance and trade-off in the complexity of embodiment.

Since the video codec supports 30 frame per second (fps) maximally andsupports diverse display formats such as Quarter Common IntermediateFormat (QCIF), Quicktime Video Graphics Array (QVGA), and CommonIntermediate Format (CIF), it can be applied to diverse applicationfields. Also, since the audio codec can compress a stereo channel at arate of less than 128 kbps, the compression efficiency is superior tothe codecs used in the conventional broadcasting systems including DAB.Therefore, spectrum use efficiency can be maximized.

FIG. 5A shows an RS encoder of the DMB system in accordance with anembodiment of the present invention. They present a structure of the RS(204, 188, t=8) encoder for generating an RS code word which is used tosatisfy the target Bit Error Rate (BER) of multimedia data and FIG. 5Bshows a structure of a packet.

In case of a DAB system, a convolutional code is used as an errorcorrecting code. If an RS code is added to the DAB system for DMB, thechannel encoder of total DMB system has a structure of concatenatedcode. Thus, the RS code can be referred to as an outer coder.

The RS (204, 188, t=8) code is embodied by using an RS (255, 239, t=8)code, and the code generator polynomial is:g(x)=(x+λ⁰)(x+λ ¹)(x+λ ²)Λ(x+λ ¹⁵)   Eq. 1wherein λ=⁰² _(HEX) .

The following is a field generator polynomial:p(x)=x ⁸ +x ⁴ +x ³ +x ²+1.   Eq. 2

Meanwhile, the RS (204, 188, t=8) code is embodied as follows.

First, 51-byte ‘0’ is added to 188-byte information data. Then, 239-byteinformation data are inputted to an RS (255, 239, t=8) encoder.

Subsequently, the added 51-byte ‘0’ is removed from the encoded 255-byteoutput data to thereby form an RS-encoded packet as described in FIG.5B.

FIG. 6 is a schematic diagram describing an interleaver of the DMBsystem in accordance with an embodiment of the present invention.

In order to remove temporal correlation between adjacent byte units, theinterleaver interleaves a 204 byte-based MPEG-2 TS packet, from which asynchronization word begins, by using a convolutional byte interleaverhaving a structure of FIG. 6.

The interleaver is formed of 12 branches and each branch is formed of aplurality of memories which are based on a unit of 17 byte×N (N=0, 1, 2,. . . , 11). Input/output switches are synchronized with each other.

For synchronization, synchronization words are transmitted alwaysthrough a ‘0’ branch and the synchronization of a deinterleaver isobtained by allocating a first recognized synchronization word to a ‘0’branch of the deinterleaver.

An interleaved data stream is allocated to a stream mode of the DABsystem and data channels for other digital broadcasting systems and thenprocessed.

Hereafter, a method and apparatus for cooperating the DMB system of thepresent invention and the conventional DAB system will be described withreference to FIGS. 7 to 10.

FIG. 7 is a block diagram describing an apparatus for cooperating theDMB system and the conventional DAB system in accordance with anembodiment of-the present invention.

In the drawing, the reference numeral ‘710’ denotes the conventional DABsystem; the reference numeral ‘720’ denotes the DMB system of thepresent invention; and the reference numeral ‘730’ denotes an ensembleremultiplexer, individually.

The ensemble remultiplexer 730 creates a new Ensemble TransportInterface (ETI) frame by remultiplexing the ETI frame inputted from theDAB system 710 with a DMB media stream and transmits the newly formedETI frame to a Coded Orthogonal Frequency Division Multiplexing (COFDM)modulator of the DAB system 710. Herein, the ensemble remultiplexer 730performs only the aforementioned remultiplexing function, or includesthe functions of the RS encoder and the interleaver additionally, orincludes all the functions of the RS encoder, the interleaver, and theDMB media processor. The system with the above-described structure makesit possible to use the conventional DAB transmission system 710,regardless of the structure, which is different according tomanufacturing companies.

FIG. 8 is a block diagram describing an apparatus for connecting the DMBsystem and the conventional DAB system in accordance with anotherembodiment of the present invention.

In the drawing, the reference numeral ‘810’ denotes the conventional DABsystem; the reference numeral ‘820’ denotes the DMB system of thepresent invention; and the reference numeral ‘830’ denotes an ETIadapter, individually.

The ETI adaptor 830 receives media stream from one or more DMB system820, converts it into an ETI frame, and outputs the ETI frame to any oneamong the ensemble multiplexer, the service multiplexer, and datainserter of the DAB system 810.

If the device in connection is the ensemble multiplexer, it receives theETI output of the ETI adapter 830 and the Service Transport Interface(STI) output of the service multiplexer, forms a new ETI frame andtransmits it to the COFDM modulator.

The ensemble multiplexer analyzes the content of the inputted STI andETI frames and forms a new ETI frame automatically based on a priorityorder defined by an administrator. This will be described more in detailwith reference to FIG. 9.

FIG. 9 is a flowchart describing an ETI frame formatting method inaccordance with an embodiment of the present invention. In theflowchart, the ensemble multiplexer/service multiplexer/data insertermaintains maximum data transmission capacity and forms a new ETI frameand a new STI frame automatically.

First, the administrator of the ensemble multiplexer establishes atransmission priority order for a sub-channel to automatically form thenew STI and ETI frame. Then, a sub-channel based on the STI and ETIframes is selected according to the above established sub-channelpriority order and it is determined whether the transmission of theselected sub-channel is possible.

If it is determined that transmission is impossible, a sub-channelhaving a data size that can be included in the remaining space of theSTI or ETI frame is searched and the process of including it into theframe is repeated in order to minimize the remaining space of the STI orETI frame to be outputted.

This can be described more in detail below.

First, at step S901, transmission priority order for a sub-channel isestablished to automatically form a new STI frame or a new ETI frame.Then, at step S902, it is established that “ETI_out=output ETI datarate=0,” “ETI_max=maximum ETI transmittable data rate,” or “STI_out=output STI data rate=0,” “STI_max=maximum STI transmittable data rate.”

Subsequently, at step S903, a sub-channel is selected based on theinputted IP datagram, the STI and ETI frames and the priority order.Then, at step S904, it is established that “sub_channel=data rate of acorresponding sub-channel.”

Subsequently, at step S905, it is determined whether“(ETI_max−ETI_out)>sub_channel” or “(STI_max−STI_out)>sub_channel” issatisfied.

If the above condition is satisfied, at step S906, it is establishedthat “ETI_out=ETI_out+sub_channel” or “STI_out=STI_out+sub_channel” andthen logic flow goes to the step S903 where a sub-channel is selectedaccording to priority order.

If the above condition is not satisfied, a step S907, it is determinedwhether there is a sub-channel having a data rate lower than“(ETI_max−ETI_out)” or “(STI_max−STI_out)” based on the inputted STI andETI frames and the priority order. If there is the sub-channel, thelogic flow goes to the step S903 where a sub-channel is selectedaccording to the priority order. If there is no such sub-channel, atstep S908, a process of forming and outputting ETI or STI frames isperformed.

FIG. 10 is a block diagram illustrating an apparatus for cooperating theDMB system and the conventional DAB system in accordance with anotherembodiment of the present invention. It presents a method of cooperatingthe DMB system with the conventional DAB system by using an Ethernetadapter.

In the drawing, the reference numeral ‘1010’ denotes the conventionalDAB system; the reference numeral ‘1020’ denotes the DMB system of thepresent invention; and the reference numeral ‘1030’ denotes an Ethernetadapter, individually.

According to the proposed method, a DMB media stream is transformed intoan Internet Protocol (IP) datagram and transmitted in the form of astream mode of the DAB system 1010. The Ethernet adapter 1030 outputsthe IP datagram to one of the ensemble multiplexer, service multiplexerand data inserter. The one of the ensemble multiplexer, servicemultiplexer and data inserter that receives the IP diagram forms new ETIand STI frames based on the method of FIG. 9.

As described above, the present invention transmits and receivesmultimedia data efficiently and stably based on the DAB system and otherdiverse digital broadcasting systems. The present invention providesdiverse interactive broadcasting service having an excellent receptionperformance without breaks by compressing video and multimedia dataefficiently, supporting an interactive service through interaction andsynchronization between objects by processing the video and multimediadata on an object basis, multiplexing video/audio/additional datastably, endowing robustness against multipath fading and the Dopplereffect that occur in a mobile channel environment by using an additionalerror correcting method.

The method of the present invention can be embodied as a program andstored in a computer-readable recording medium such as CD-ROM, RAM, ROM,floppy disks, hard disks, and magneto-optical disks.

As described above, the present invention can provide an interactivemultimedia data service by using the conventional DAB system and otherdiverse digital broadcasting systems and it can transmit multimedia dataof diverse formats such as mobile TV, Differential Global PositioningSystem (DGPS), Location Based Service (LBS), Pay Per View (PPV), trafficinformation, stock information, weather forecast and the like.

Also, the present invention can maximizes the spectrum use efficiency byusing highly efficient multimedia data compression technology and it canembody a multimedia data service efficiently by adding a DMB processingmodule to the conventional DAB and other diverse digital broadcastingsystems. The present application contains subject matter related toKorean patent application No. 2003-57531, filed in the KoreanIntellectual Property Office on Aug. 20, 2003, the entire contents ofwhich is incorporated herein by reference.

While the present invention has been described with respect to certainpreferred embodiments, it will be apparent to those skilled in the artthat various changes and modifications may be made without departingfrom the scope of the invention as defined in the following claims.

1. A digital multimedia broadcasting (DMB) system, comprising: anencoding means for encoding an audio/video signal; a synchronizing meansfor synchronizing media stream, additional data, interactive serviceobjectifying data that are outputted from the encoding means; amultiplexing means for multiplexing the media stream outputted from thesynchronizing means; an error correction encoding means for performingadditional error correction encoding on the media stream outputted fromthe multiplexing means; an interleaving means for removing temporalcorrelation between adjacent byte units within a data stream outputtedfrom the error correction encoding means; and a transmitting means fortransmitting a DMB media stream outputted from the interleaving means.2. The system as recited in claim 1, wherein the audio/video signal isobtained by converting multimedia source data into data stream of apredetermined format through a preprocessing.
 3. The system as recitedin claim 1, wherein the encoding means includes a ‘Moving PictureExperts Group (MPEG)-4 Part 2’ codec or a ‘MPEG-4 Part 10 Advanced VideoCoding (AVC)’ codec as a video encoder; and an ‘Advanced Audio Coding(AAC)’ codec, an ‘AAC+’ codec, or a ‘Bit Sliced Arithmetic Coding(BSAC)’ codec as an audio encoder.
 4. The system as recited in claim 1,wherein the synchronizing means includes: an Object Descriptor(OD)/Binary Format for Scene (BIFS) generating means for generatingOD/BIFS for interactive service; an Initial Object Descriptor (IOD)generating means for generating an IOD; and a sync layer packetizingmeans for synchronizing media streams outputted from the encoding meansand the OD/BIFS generating means.
 5. The system as recited in claim 4,wherein the multiplexing means includes: a PES packetizing means forgenerating a Program Elementary Stream (PES) packet based on a packetoutputted from the sync layer packetizing means; a section packetizingmeans for generating a predetermined section based on a packet outputtedfrom the sync layer packetizing means; a Program Service Information(PSI) generating means for generating PSI based on data outputted fromthe IOD generating means; and a transport stream (TS) packetizing meansfor packetizing data outputted from the PES packetizing means, thesection packetizing means and the PSI generating means into transportstream.
 6. The system as recited in claim 1, wherein the errorcorrection encoding means is utilized to satisfy the target Bit ErrorRate (BER) performance of multimedia data, and the error correctionencoding means uses an RS encoder and has a structure of an RS encoder(204, 188, t=8) substantially.
 7. The system as recited in claim 1,wherein the interleaving means is formed of 12 branches, and eachbranch, which is formed of memories based on a 17-byte×N unit (N=0, 1,2, . . . , 11), has input and output switches synchronized with eachother, and a synchronization word for synchronization is transmittedalways through a ‘0’ branch and the synchronization of a deinterleaveris obtained by allocating the first recognized synchronization word tothe ‘0’ branch.
 8. The system as recited in claim 1, wherein thetransmitting means utilizes a digital audio broadcasting system (DAB), adigital television (TV) broadcasting system, a digital satellitebroadcasting system, and a digital cable broadcasting system.
 9. Thesystem as recited in claim 1, wherein the transmitting means iscooperated with any one among the DMB system, an ensemble remultiplexer,an Ensemble Transport Interface (ETI) adapter, and an Ethernet adapter.10. The system as recited in claim 1, wherein the DMB system, which isbased on the digital audio broadcasting (DAB) system, a digitaltelevision (TV) broadcasting system, a digital satellite broadcastingsystem, and a digital cable broadcasting system, does not include theerror correction encoding means and/or the interleaving means accordingto system performance in a high-speed mobile channel environment.
 11. Adigital multimedia broadcasting (DMB) method, comprising the steps of:a) encoding video/audio data at a high efficiency for data compression;b) synchronizing a media stream encoded in the step a), a media streamfor an additional data service, and a media stream by an objectificationfor an interactive service; c) multiplexing a media stream synchronizedin the step b); d) encoding and interleaving for correcting an error tobe occurred in a media stream multiplexed in the step c); and e)transmitting a stream interleaved in the step d).
 12. The DMB method asrecited in claim 11, wherein, in the step a), preprocessed video signalsare encoded by using a ‘Moving Picture Experts Group (MPEG)-4 Part 2’encoder or a ‘MPEG-4 Part 10 Advanced Video Coding (AVC)’ encoder; andpreprocessed audio signals are encoded by using any one among an‘Advanced Audio Coding (AAC)’ encoder, an ‘AAC+’ encoder, and a ‘BitSliced Arithmetic Coding (BSAC)’ encoder.
 13. The DMB method as recitedin claim 11, wherein the step b) includes: b1) generating an ObjectDescriptor (OD)/Binary Format for Scene (BIFS) for interactive service;b2) generating an Initial Object Descriptor (IOD); and b3) packetizingthe media stream for synchronizing encoded media streams outputted fromthe steps a) to e) and b1) and the OD/BIFS media stream.
 14. The DMBmethod as recited in claim 11, wherein the step c) includes the stepsof: c1) generating a Program Elementary Stream (PES) packet based on apacket outputted from the step b3); c2) generating a predeterminedsection based on a packet outputted from the step b3); c3) generatingProgram Service Information (PSI) based on data outputted from the stepb2); and c4) packetizing data outputted from the steps c1) to c3) intotransport stream.
 15. The DMB method as recited in claim 11, wherein,the error correction coding of the step d) is performed to satisfy thetarget Bit Error Rate (BER) performance of multimedia data, and aReed-Solomon (RS) encoder is used for encoding the error correction codeand a structure of an RS (204, 188, t=8) encoder is adoptedsubstantially.
 16. The DMB method as recited in claim 14, wherein, theinterleaving of the step d) is formed of 12 branches, and each branch,which is formed of memories based on a 17-byte×N unit (N=0, 1, 2, . . ., 11), has input and output switches synchronized with each other, and asynchronization word for synchronization is transmitted always through a‘0’ branch and the synchronization of a deinterleaver is obtained byallocating the first recognized synchronization word to the ‘0’ branch.17. The DMB method as recited in claim 11, wherein, the step e) includesthe steps of: e1) establishing a transmission priority order withrespect to a sub-channel for automatic formation of an Service TransportInterface (STI)/Ensemble Transport Interface (ETI) frame in the digitalbroadcastings system; and e2) selecting a sub-channel based on theabove-established sub-channel priority order and the STI/ETI inputframe, determining whether transmission is possible, if transmission isimpossible, searching a sub-channel that can be included in theremaining space of the STI/ETI frame, including the selectedsub-channel, and minimizing the remaining space in the STI/ETI frame tobe outputted by repeating the process.
 18. The DMB method as recited inclaim 17, wherein, the transmission process of the step e) is performedin digital broadcasting system, such as, a digital audio broadcastingsystem, a digital TV broadcasting system, a digital satellitebroadcasting system, and a digital cable broadcasting system.
 19. TheDMB method as recited in claim 18, wherein the DMB system based on theconventional digital broadcasting system is cooperated with any oneamong, an ensemble remultiplexer, an Ensemble Transport Interface (ETI)adapter, and an Ethernet adapter.
 20. The DMB method as recited in claim19, wherein the DMB system does not include the error correctionencoding means and/or the interleaving means in a high-speed mobilechannel environment such as the digital audio broadcasting system, adigital television (TV) broadcasting system, a digital satellitebroadcasting system, and a digital cable broadcasting system.
 21. Acomputer-readable recording medium for recording a program thatimplement a digital multimedia broadcasting (DMB) method, whichcomprises the steps of: a) encoding video/audio data at a highefficiency for data compression; b) synchronizing a media stream encodedin the step a), a media stream for an additional data service, and amedia stream by an interactive service objectification for aninteractive service; c) multiplexing a media stream synchronized in thestep b); d) encoding and interleaving for correcting an error to beoccurred in a media stream multiplexed in the step c); and e)transmitting a stream interleaved in the step d).